TUNPROTEC® - Intelligent fixed fire fighting systems for sub surface complexes

Reliable, simple to operate, fast and easy to install and commission, low requirements to maintenance and the most environmental friendly solution on the market re. water consumption and power.

The TUNPROTEC® system contains the following individual systems:

  • Detection System - Comprises the VFK Deflametec-TPT flame detectors and VFK Deheattec-TPT linear heat detector installed within the fire-zone.
  • Valve Station - Comprises the necessary valves, switches and controls to automatically operate and monitor the hydraulic system and the supply of water to the fire-zone.
  • Interface System - Comprises the VFK MCP-TPT Control Panel for entire system control, monitoring and for relaying signals to connected systems, including SCADA and alarm systems.
  • Model N-Pipe System - Installed within the fire-zone, protects the tunnel through use of its low pressure Model BM-1L watermist nozzles.
  • Pump Unit – Electric or diesel fueled pumps, with/without 100% redundancy and with/without jockey pump. Due to the low water and pressure requirements of the TUNPROTEC® system, the Pump Units can be designed with 100% redundancy at low additional costs.
  • Hydrant Station (Optional) – The low pressure class of the system allows for the implementation of access points to system water for firefighting personnel. By including TUNPROTEC® Hydrant Stations, the entire system can be fed by one Pump System and supply pipe.

The entire TUNPROTEC® system is supplied ready to install and includes:


  • Diesel and/or Electrical Pump Unit
  • Linear Heat Detector and Flame Detectors
  • Zone Valve Stations and Fire-Zone Control Panels with optional protective cabinets
  • Hydrant Stations with optional protective cabinets
  • System Control Panel with means for forwarding signals to alarm systems such as SCADA systems
  • Preliminary hydraulic calculations and design draft supplied by VID Fire-Kill ApS



Also features:


  • All components in Stainless Steel AISI 316L with PN16 ratings.
  • Electrical containers with dust- and waterproof IP67 ratings.
  • Allows for use of standard plastic supply pipes due to low system pressures.
  • All relevant hydraulic points capable of being monitored through pressure switches and System Control Panel.

The process of protecting tunnels

The TUNPROTEC system actively monitors for fires within the tunnel, assesses potential false alarms and effectively combats tunnel fires before the fire disasterous conditions can develop.

Picture describing the TUNPROTEC system layout within the tunnel structure.

System in standby

During the system design phase, the tunnel will be divided into 20-30 m long fire-zones, each containing the TUNPROTEC® Detection System, TUNPROTEC® Valve Station and the Model N-Pipe System.


The entire system is monitored by the TUNPROTEC® Control System, however each individual fire-zone is designed to be fully functional even when not connected to the Interface System.

Picture describing the TUNPROTEC system detecting a fire within a given fire-zone.

Fire detected

While in standby, the TUNPROTEC® Detection System monitors the tunnel and detects developing fires. The Detection System monitors different parameters and requires three separate detections to initiate an alarm state.

Immediately upon detection of fires, the Detection System alerts the Valve Station and Control System of the developing fire and the designated personnel and peripheral systems are alerted of the danger.

Picture describing the TUNPROTEC system activating the zone valves within the given fire-zone and the adjacent fire-zones.

Control and suppression

Upon receiving the alert, the Valve Station activates and supplies the low pressure watermist system for the specific fire-zone and adjacent fire-zones. By activating the adjacent fire-zones, the TUNPROTEC® system limits the spread of fire and thermal-effects of the fire, cools the tunnel structure and stops the development of back layer, allowing firefighting personnel to safely enter the tunnel early and people inside the tunnel to save themselves.

An effective means of tunnel fire protection

Utilizing low pressure watermist

The self-sustaining nature of fires, through pyrolysis and oxidation, allows for rapid growth. To fight this growth, the TUNPROTEC® system utilizes a unique mix of small droplet sizes compliant with CEN/TS 14972 (dv.0.90). The small droplet sizes and the lower pressures allows the TUNPROTEC® system to effectively control and suppress tunnel fires with a typical 80% - 99% reduction in water consumption at lower power requirements compared to other systems available on the market. 

The small droplet sizes make the TUNPROTEC® system capable of fighting tunnel fires through the below mentioned principles:

Picture showing the TUNPROTEC spray.
Picture describing how the TUNPROTEC system wets surfaces within the activated fire-zone.

Limiting fire spread

Limiting the pyrolysis effect

Through the spread of the small sized droplets, the watermist system covers the entirety of the fire-zone, wetting surfaces and hindering material in the vicinity of the developing fire from initiating the pyrolysis process. By limiting the development of pyrolysis gasses, the watermist isolates the fire from its fuel source, hindering it from spreading without spending additional energy.


This means of isolating fires from fuels, is the method most commonly used by conventional sprinkler systems, however the small droplets from low pressure watermist systems do not just stop at limiting the development of pyrolysis gasses.

Cooling the fire and the surrounding structure

Lowering temperatures

Due to the small droplet sizes produced by watermist, the system increases the effective surface area of its droplets by a factor of 1700. Through this increased surface area, the droplets are capable of absorbing more energy from the fire in the form of heat. This increased heat absorption minimizes the fires ability to compromise the tunnel structure and decreases the speed of which the fire can spread. 

Picture describing how the TUNPROTEC system absorbs the heat produced by tunnel fires, reducing the ambient temperature within the activated fire-zone.
Picture describing how the TUNPROTEC system reduces the oxygen concentration in the vicinity of the tunnel fire.

Suffocating the fire

Limiting the oxidation process

Once droplets have absorbed sufficient energy from the fire, the droplets will proceed to evaporate. As the volume of water increases as it moves from a liquid to gaseous state, the resulting inert water vapor will displace more of the present oxygen and combustible pyrolysis gasses away from the fire – Effectively starving or suffocating the fire and drastically limit its ability to develop additional energy in the form of heat.

Allowing firefighters to enter and evacuees to escape

Removing back layering

A common concern when protecting tunnels is the development of back layering as smoke travels upstream through the tunnels forced ventilation. This back layering effect limits visibility and in turn hinders firefighting personnel from entering and securing the tunnel due to their personal safety.

In conjunction with limiting the fuel consumption and development of smoke, the TUNPROTEC® system actively hinders back layering and buildup of toxic gasses from developing and the thermal expansion of these gasses, thus allowing for lower forced ventilation speeds (<3 m/s) within the tunnel. The resulting environment allows firefighting personnel to safely enter the tunnel, removed casualties and actively fight the fire from short distances, further limiting the damaging effects of fires within tunnels.

Picture describing the TUNPROTEC systems ability to effectively reverse back layering at reduced forced ventilation speeds.

Tunnel fire protection through lower pressures

Unique benefits of TUNPROTEC®

-Lower water consumptions minimizes spatial requirements of system

-Lower water consumptions minimizes excess water within tunnel during activation and drainage needs

-Lower pressures equals quicker, safer and cost-effective system

-Lower pressures allowes for inclusion of more robust and reliable system components

-Lower pressures allows for implementation of plastic piping

-Lower pressures allows for integration of Hydrant Stations

-Reduces needs for passive fire protection such as fire-lining, etc.

-Lower requirements to forced ventilation from 7-8 m/s to 2-3 m/s

-System supplied in AISI 316L stainless steel minimizes corrosion

-The system can be supplied entirely in SIL2 approved materials

Picture of the Model N-Pipe Type 3V-BM-1L nozzle pipe.
Table describing the differences between typical spinkler and deluge systems, and low pressure watermist systems in regards to system requirements.

Lower water consumption and smaller system dimensions

Benefits compared to sprinkler/deluge systems

-Lower water consumption ( < 80% savings)

-Smaller pipe dimensions resulting in lower spatial requirements to pump stations, reservoirs, valves and water mist system

-Fewer water damages after activation and lower drainage needs

-Better hydraulic balance allows for more consistent flow related to pressure loss

-Supplied in AISI 316L stainless steel giving a lower risk of corrosion

Lower pressures, water and power consumptions

Benefits compared to high pressure water mist systems

-Lower installation costs due to faster installation times due to fewer components

-Fewer components equals less obstruction within tunnel resulting in a lower need for maintenance

-Lower water consumption and system pressures

-More robust and reliable and larger waterways in nozzles giving a lower risk of clogging and less need for filtration

-Substantial lower power requirements allowing for 100% redundancy

Table describing the differences between typical high pressure watermist systems and low pressure watermist systems in regards to system requirements.

Test & Approvals

TUNPROTEC® - A proven solution

Picture of the UPTUN logo.

Featured in UPTUN WP2 D251 Guideline

The goal of the UPTUN WP2 D251 initiative by the European Commission was to develop cost-effective, sustainable and innovative upgrading methods for fire safety with water based systems in existing tunnels and the establishment of a manual of good practice in tunnels. VID Fire-Kill and the TUNPROTEC® participated in the study and the TUNPROTEC® system was successfully tested to fires between 3 MW and 28 MW.

Picture of Runehamar fire test.

Runehamar Full Scale Tunnel Tests to 100MW Fires

In collaboration with SP-SINTEF, VID Fire-Kill conducted a number of full scale fire tests in the 1.8 km long Runehamar Tunnel in Norway.

The fire tests were successfully performed to both diesel pool fires and solid fuel fires from 25 MW up to 100 MW.


Click here to see the 100 MW full scale fire test from the Runehamar Tunnel test series.

Picture of the CE-logo.

CE – Conformité Européene

All electrical components of the TUNPROTEC® system comply with the EN54 standard and are CE-marked.

TP logoer

Additional Tests and Approvals

The TUNPROTEC® system has successfully been tested to and passed many different tests and has received various approvals, including:


- MSC Circ. 1165 water mist nozzle component test approval

- EN54 approval on detection and control system

- NFPA750 and NFPA502 compliant

- Certified Mean Time to Failure (MTTF) rating of 150 years

- SIL2 approved/certified

Graph describing the TUNPROTEC systems capabilities of reducing temperature buildup and reversing back layering on a 30 MW fire. Back layering reversed and temperature returned to normal levels within one minute after TUNPROTEC activation.

Test Results

The TUNPROTEC® systems capability to hinder temperature buildup and minimizing back layering in tunnel fires is apparent when viewing the results from the Runehamar Tunnel tests described in the chart above. As described by the temperature and ventilation curves above, the TUNPROTEC® system effectively returned the thermal expansion of the smoke development and temperature buildup to minimal values within the first minute after activation, reducing temperatures from 400 °C to normal temperatures and completely stopping the development of back layer. By preventing these two devastating factors, the TUNPROTEC® system prevents potential catastrophic fires from developing and allows firefighters to enter the site and actively fight the fire almost immediately after system activation.

Get the latest updates delivered right to your inbox

Tunprotec Logo
  • sales@tunprotec.com
  • +45 62621024
  • Svalbardvej 13
  • 5700 Svendborg
  • Denmark